Application of Adaptive Observer to Sensorless Induction Motor via Parameter-Dependent Transformation

This brief addresses the adaptive observer design problem for sensorless induction motor (IM) drives with unknown resistances. In the literature, difficulty is found when applying several well-developed adaptive observer designs to IM dynamics. Hence, by introducing a parameter-dependent transformation, in the new coordinate, the IM dynamics manifest the attributes that facilitate the adaptive observer design. Although the classic designs that require linear-in-parameters result in overparameterization, the proposed nonlinearly parameterized adaptive observer demonstrates a good performance, as illustrated by the simulation and experimental results.